Lost

One of the castaways is chosen to descend into the mysterious hatch, and Shannon stumbles upon a shockingly familiar face in the jungle.

Michael blames Sawyer for the abduction of Walt and promises to bring his son back. Meanwhile, Kate releases herself from Desmond's captivity and escapes.

Jack, Locke and Kate learn more secrets about the hatch. Meanwhile, Sawyer, Michael and Jin wonder if their captors are fellow survivors or the "Others."

Disturbing memories from Hurley's past cause him to struggle with a task to watch over the food storage locker. Meanwhile Claire uncovers a shocking piece of information.

Michael sets off into the jungle to find Walt, but discovers that he is not alone. Meanwhile, Sawyer and Jin are ordered by their captors to take them to their camp.

Sawyer's wound becomes life-threatening as he, Michael and Jin make their way through the interior of the island with the tail section survivors.

The harrowing first 40 days of the 23 tail section survivors are revealed, introducing Ana Lucia, Mr. Eko, Libby, Cindy, Bernard, and Goodwin – detailing the first terrifying days and battling the dreaded "Others".

Tempers flare when Ana Lucia and her group stumble upon Sayid and the other castaways.

Kate's original crime that started her life on the run is revealed. Meanwhile, the survivors lay one of their own to rest, and Mr. Eko has a surprise for Locke .

Mr. Eko interrogates Charlie about the Virgin Mary statue, Claire begins to lose faith in Charlie.

Jack, Locke and Sawyer track Michael while he looks for his son, and meet "The Others".

When Charlie's vividly surreal dreams lead him to believe Claire's baby, Aaron, is in danger, Locke suspects Charlie may be using drugs again.

Survivors fear that "The Others" may have returned when Sun is injured during a failed kidnapping attempt. Meanwhile, tension escalates between Jack, Locke, Kate and Ana Lucia over control of the hatch computer.

Mysterious French woman Danielle Rousseau returns to lead Sayid to a mysterious captive who claims he crashed on the island.

When Claire's baby falls ill, she becomes determined to find out what happened to her to regain her memory during her captivity with the Others.

When Sun comes to the realization that she might be pregnant, she struggles over whether to tell Jin about the situation; after no success from Jack or Sayid, Ana Lucia is called in by Locke to interrogate the prisoner Henry Gale.

When the hatch suddenly takes on a life of its own, Locke is trapped alone in the bunker and is forced to enlist the help of an unlikely ally.

Hurley thinks the island is affecting him in a very strange way, and Libby attempts to offer support; Hurley recalls his past in a mental hospital with his friend Dave.

Bernard tries to convince the survivors to build a S.O.S. signal with rocks on the sand, hoping to be seen by a satellite or an airplane.

Jack and Kate bring an exhausted Michael back to camp where he has news about "The Others". Meanwhile, Ana Lucia attempts to get Henry Gale to confess to being a spy.

Mr. Eko enlists Locke to help find a secret location he believes houses answers to the island's mysteries; Henry Gale manages to escape from the hatch.

Michael's whereabouts during his 13 days in captivity in the "Others" camp are detailed; Michael tries to convince Jack to help him mount a search party for his son Walt.

Jack and Sayid come up with a plan to confront "The Others."

The success or failure of Jack and Sayid's plan to confront "The Others" is revealed.